As an N-alkyl bis(perfluoroalkylsulfonyl)imide that is a sulfonic acid derivative, the N-methyl bis(trifluoromethanesulfonyl)imide whose alkyl group is methyl group (CH3) and perfluoroalkyl group is trifluoromethyl group (CF3), and the N-methyl bis(nonafluorobutanesulfonyl)imide whose alkyl group is a methyl group (CH3) and a perfluoroalkyl group is a nonafluorobutyl group (C4F9), have been known.
As methods for producing N-alkyl bis(perfluoroalkylsulfonyl)imide, the methods disclosed in Non Patent Literature (NPL) 1 and NPL 2 are known. Specifically, in the method disclosed in NPL 1 for producing N-methyl bis(perfluoroalkylsulfonyl)imide, bis(perfluoroalkylsulfonyl)imide acid is methylated using trimethyl orthoacetate (CH3C(OCH3)3)) as a methylating agent. In the method disclosed in NPL 1, trifluoromethyl group (CF3) and nonafluorobutyl group (C4F9) are used as a perfluoroalkyl group.
In the method disclosed in NPL 2 for producing N-methyl bis(perfluoroalkylsulfonyl)imide, bis(perfluoroalkylsulfonyl)imide acid is methylated using diazomethane (CH2N2) as a methylating agent. In the method disclosed in NPL 2, nonafluorobutyl group (C4F9) is used as a perfluoroalkyl group.
In addition, as an N-alkyl bis(fluorosulfonyl)imide, N-methyl bis(fluorosulfonyl)imide, which has a methyl group as an alkyl group, and N-ethyl bis(fluorosulfonyl)imide, which has an ethyl group as an alkyl group are known. As methods for producing them, the methods, in which bis(fluorosulfonyl)imide silver salt and alkyl iodide are reacted, described in NPL 3 is known.